US rock band Metallica has broken its long-standing refusal to join Apple's iTunes service and finally made its music catalogue available on the music download site.

A posting on the group's website reads: "Over the last year or so, we have seen an ever-growing number of Metallica fans using online sites like iTunes to get their music.

"So, in continuing with the tradition of offering our albums for sale online (which we've been doing for a few years through various sites), as well as making our live concerts available for download in their entirety (through the livemetallica.com site), we are now offering fans the opportunity to obtain our songs individually."

Metallica was one of the few remaining major groups, alongside The Beatles and Radiohead, that have resisted selling individual tracks via services such as iTunes.

However, only iTunes music stores in the US and Canada are offering Metallica songs at present.

"This is unfortunately due to the fact that our record company overseas doesn't seem to want to play ball with us on this at the moment," said the Metallica statement.

"Hopefully this will get sorted out ASAFP, but we didn't want our fans in North America to have to wait any longer while our overseas record company tries to get their s**t together."

To make the digital albums more attractive to their existing fanbase, the band has added a number of previously unreleased live tracks on to the group's first four albums, Kill 'Em All, Ride The Lightning, Master of Puppets, and And Justice For All.